Hasil untuk "Physical and theoretical chemistry"

Yukhta Mariia, Bespalova Iryna, Koroleva Anastasia et al.

In recent years, nanotechnology has had a profound impact on low-temperature preservation, offering advanced solutions that significantly improve the storage of biological samples. Low-temperature preservation is crucial for numerous fields, such as medicine, agriculture, and biological research, where maintaining the viability and integrity of cells, tissues, and organs over extended periods is essential. Integration of nanotechnology into low-temperature preservation protocols represents significant advancement, enabling more effective, safer, and efficient storage of biological specimens. Moreover, it affords effective strategies for solving one of the most pressing challenges in transplantology and cryobiology today – cryopreservation of whole organs. This not only enhances the viability of cryopreserved materials but also broadens the scope of their applications in science and medicine. This article is a traditional review that summarizes the limitations of methods for the low-temperature storage of biological systems of animal origin and the current advances in nano-assisted technologies aimed at overcoming them. We have made every effort to accurately detail the role of inorganic nanoparticles in enhancing the field of cryobiology, paying special attention to their application in various methods of low-temperature preservation, specifically in hypothermic storage, slow-freezing cryopreservation, and vitrification. Finally, current challenges are critically assessed and perspectives are discussed.

Nobuyuki IMANISHI, Daisuke MORI, Hikari SAKAEBE et al.

This special issue of Electrochemistry features selected papers from the 65th Battery Symposium in Japan, held in November 2024, which marked a full return to in-person meetings after the COVID-19 pandemic. The symposium saw record participation, highlighting strong interest in lithium-ion batteries, all-solid-state batteries, and emerging chemistries such as sodium-ion and lithium–sulfur systems. Progress in electrolyte design, interfacial science, and data-driven approaches was also emphasized. Additionally, several contributions focused on fuel cell research, reflecting the expanding scope of electrochemical energy technologies. We hope this collection stimulates further innovation in energy storage and conversion.

Ganapathy Ganesh Prabhu, Kaliyappan Shunmuga Priya, Ramamoorthy Venkada Lakshmi et al.

Foud Nihad Abed, Mustafa Mahdi Abdulridha, A. A. Hamad Mohamad et al.

A smart, environmentally friendly superabsorbent polymer was prepared using solvents. It was polymerization on the microwave rays at a medium capacity and for 25 minutes, where the yellow gel was obtained. The polymer was cut and washed with absolute ethanol and methanol and was dried at a temperature of 60°C. Then, the polymer was extracted and milled with ceramic fat until obtaining a very soft powder, and the tests were taken as a formula for a scanning electron microscope and infrared spectrum. The results showed that the absorption value of polymer is at the equivalent acid function, where the absorption capacity was 467.32 grams. At room temperature, the water retention rate was 71%, and at 50°C, it was 52%, and the gel content was 90%. The results showed an improvement in the properties of the gypsum soil in terms of virtual density, porous, and acidic function, reaching 7.3%. The proportion of significant elements (P, N, Ca, K, Na) and moisture content in the soil was 64%, the cumulative tip amount and the consistency of soil granules through wet and dry palm, penetration resistance, electrical conductivity 4 ms, and organic material content were as follows, and the results were very high.

Meng C. Lin, Tatyana F. Svitova

Hypothesis: Biophysical property and water evaporation retardation through a lipid nanofilm can be altered by model tear protein and topical ophthalmic formulation. Experiment: Evaporation rate and dynamic surface pressure were measured using a sessile drop technique. Water evaporations from 5 individual protein solutions, their mixture, and 6 ophthalmic formulations were quantified. Biophysical property and evaporation through model lipid nanofilms spread on model electrolyte solutions, tear protein solutions, and ophthalmic formulations were assessed. Findings: Model lipid nanofilms spread on electrolyte solution reduced evaporative fluxes by 43–60%. Evaporative fluxes from individual protein solutions without lipids were 3–19% lower than from electrolytes solution. Evaporative fluxes through lipid nanofilms were decreased by the presence of albumin or lactoferrin in solutions but increased by lysozyme and mucin.Evaporative fluxes from ophthalmic formulations were 10–43% lower than from electrolyte solution. Evaporations through lipid nanofilms spread on formulations were higher than through lipids on electrolyte solution. Model lipid nanofilms spread on Diquas appeared more rigid than on electrolyte solution but showed softening when spread on Refresh Mega-3.Some proteins and ophthalmic formulations altered model lipid nanofilms evaporative barriers. Ophthalmic formulation induced changes in biophysical property of model lipid nanofilms in vitro may suggest possible tear film destabilization in vivo.

Yalan Li, Bo Deng

The Wiener index is defined as the summation of distances between all pairs of vertices in a graph or in a hypergraph. Both models—graph-theoretical and hypergraph-theoretical—are used in mathematical chemistry for quantitatively studying physical and chemical properties of classical and nonclassical organic compounds. In this paper, we consider relationships between hypertrees and trees and hypercycles and cycles with respect to their Wiener indices.

Zhengping Zhao, Sitao Shen, Feng Chen et al.

Using sodium lignosulfonate as carbon source, microspheres were prepared by ultrasound. Molybdenum disulfide was synthesized directly by hydrothermal method and grown on the surface of lignin microspheres. Then, molybdenum disulfide modified porous microsphere carbon material was prepared by pyrolysis at high temperature and used as the cathode material of lithium ion battery to study its electrochemical properties. The size of lignin microspheres was about 500 nm. The spacing of the molybdenum disulfide coating on the surface was 0.52 nm. After sintering, the diameter of microspheres is about 300 nm and the surface aperture of MoS2@C microspheres is about 300 nm. The initial chargedischarge specific capacity was 1049 mAh/g, and the retention rate of 200 charge-discharge specific capacity was 87.3%. The scanning rate of cyclic voltammetric curves show that the electrical properties of MoS2@C microspheres are stability.

Natália F Campos, Celmy MBM Barbosa, Joan M Rodríguez-Díaz et al.

This study proposes the use of activated charcoal made from Umbaúba wood as an adsorbent for the removal of naphthenic acid in an aviation kerosene model mixture. The activated charcoal was characterised as mesoporous with a carbon graphite profile and presented pH pzc equal to 10.5. The best working conditions were obtained for activated charcoal levels of <0.09 mm and 300 r min −1 . The system reached the equilibrium after 360 min, without significant statistical difference for the pseudo-first- and pseudo-second-order kinetic models. The Weber–Morris and Boyd models corroborated the conclusion that adsorption is not controlled only by the intraparticle diffusion step. For the equilibrium study, the adsorptive capacity obtained was of 1.1 g g −1 , with the Brunauer–Emmett–Teller model better correlating with the experimental data. Given the results obtained, the activated charcoal demonstrated to have a remarkable potential for removing naphthenic acid in an aviation kerosene model mixture.

J. LaRue, O. Krejčí, O. Krejčí et al.